// --- Time Pulse Service Worker ---

const CACHE_NAME = 'timepulse-v1';

// Files to cache (App Shell)
const filesToCache = [
  '/',
  '/index.html',
  '/style/style.css',
  '/js/main.js',
  '/js/ui.js',
  '/js/api.js',
  '/js/utils.js',
  '/manifest.json',
  '/icons/icon-192x192.webp',
  '/icons/icon-512x512.webp'
];

// --- Install Event ---
self.addEventListener('install', event => {
  console.log('[SW] Install event');
  event.waitUntil(
    caches.open(CACHE_NAME)
      .then(cache => {
        console.log('[SW] Caching app shell');
        return cache.addAll(filesToCache);
      })
  );
  self.skipWaiting(); // Activate worker immediately
});

// --- Activate Event ---
self.addEventListener('activate', event => {
  console.log('[SW] Activate event');
  event.waitUntil(
    caches.keys().then(keys => 
      Promise.all(
        keys.map(key => {
          if (key !== CACHE_NAME) {
            console.log('[SW] Removing old cache:', key);
            return caches.delete(key);
          }
        })
      )
    )
  );
  self.clients.claim(); // Become available to all pages
});

// --- Fetch Event ---
self.addEventListener('fetch', event => {
  // Ignore non-GET requests and API calls
  if (event.request.method !== 'GET' || event.request.url.includes('/api/')) {
    return;
  }

  event.respondWith(
    caches.match(event.request)
      .then(response => {
        // Return cached file OR fetch from network
        return response || fetch(event.request).then(fetchResponse => {
          // Optionally cache new files on the fly
          return caches.open(CACHE_NAME).then(cache => {
            cache.put(event.request, fetchResponse.clone());
            return fetchResponse;
          });
        });
      })
      .catch(() => {
        // Optional: return a fallback page or image here
      })
  );
});